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' -UNITED STATES PATENT f OEEICE.

, WILLIAM H. H. BOWERS, OE SALT LAKE CITY, UTAH TERRITORY, AssIGNoE E ONE-HALE To STEPHEN r. M. TASKEE, OE PHILADELPHIA, PA.

oRusHlNG-ROLL.

SPECIFICATION forming part of Letters Patent No 294,361, dated March 4, '18.84.

ApplicationfiledJulylG,1883. (Nomodel.) i i all whom it irl/ay concern.-

Beit known that I, WILLIAM H. H. BOW- ERS, of Salt Lake City, UtahTerritory, have invented an Improvement in CrushingRolls,

of which the following is a specification.

lMy invention relates to what are known,

.technically,as Cornish rolls,77 which are used for crushing ores and other hard'substances.

As heretofore constructed, Cornish rolls have lconsisted either of two straight-faced metal Arollers set upon horizontal shafts erected face to face and caused to revolve in opposite di-v rections toward eachother, or else have consisted of two double-conical rolls similarly mounted and driven, each of which rolls con-| discharged below in a state of 'subdivision from between said rolls. These rolls have been sustained in any suitable housing, and usually been driven by toothed spur-wheels, substantially in the'manner represented in the drawings. l 4

Incident to the employment of the abovementioned straight-faced Cornish rolls has'been the disadvantage that they have worn out as to the central or median portions of their peripheral faces more quickly than as to the edge portions, with the result that both of the rolls have become concave, and have therefore become worthless because incapable of adjustment for fine crushing.

Incident to the employment of the abovementioned double-conical rollslhas been the disadvantage that they have worn out more quickly as to their extremities and as to their central portions than as to the vportions intermediate between'the centers and the extremities, while incident to the rolls above mentioned,

of which one is convex and the other concave,

`has been the disadvantage that they have median portions .than as to the other portions of their acting peripheral faces.

Ihave discovered that by making one of the rolls convex as to its peripheral face and the other correspondingly concaveas to its peripheral face, and by making the proportions of the rolls such that their diameters on central vertical planes are `the same, the wear of the acting peripheral faces of the rolls will be even throughout the entire extent of said faces-a -result due to the fact that the edge portions ofthe acting face ofthe concave roll, being of greater circumferential extent than the correspondingly opposite edge portions of the acting face of the convex roll, travel faster than the same portions of the convex roll, and therefore occasion a rubbing or rolling action upon the material happening to be between the edge portions 'of the peripheral faces of the rolls sufficient to occasion the wearing away of said portions equally and to the same extent as the central portions of the two rolls, which central portions, traveling at the same rates of speed, do not rubbut merely crush the material, and are worn away by the action of crushing only as opposed to the action of rotation of the shafts and rolls. Y

Fis adriving-shaft equipped with pulleys G, and with a driving-pinion, H,which is engaged with'a driving spur-wheel, I, upon .the shaft of the concave roll. Motion imparted to the driving-shaft occasions the rotation of the roll-shafts through the instrumentality of the pinion and spur-wheels described.

In the drawings I have represented but one with each other so as to occasion an opposite IOO convex and one concave roll. ever, to state that I contemplate the employment of two or of a series of rolls side by side upon the same shaft, and set to face a corresponding` number of correspondingly oppositely-curvcd rolls upon the opposite shaft, the arrangement being,` one of convenience merely, to increase the effective capacity of the machine wit-hout in any wise'altering its principle of operation.

Having` thus described my invent-ion, I claim and desire to secure by Letters Patent- As an improvement in crushing-rolls7 the combination, substantially as and for the purposes described, of two oppositely-placed or I desire, how- I opposing rolls, one of which is convex as to its peripheral or acting face, and the other oi' which is correspondingly concave as to its peripheral or acting,` face, and both of which are isodiametric as to the central portions of their acting faces and travel at the same rate of' speed, and means for occasioning the reverse rotation of the said two rolls.

In testimony whereof I have hereunto signed my naine this 16th day of May, A, l). 1883.

VILLIAM H. H. BO\VERS.

In presence of- J. BoNsirLL TAYLOR, JOHN JoLLEY, Jr. 

